" Còn" has a lot of meanings. I'll show you some examples below so that u can know when u should use this word
1) "How's it going, Quy?, are u still practising English?" The word "Still" in this case means "Còn"; this is the sentence that's written in Vietnamese :" Dạo này thế nào rồi, Quý? Bạn vẫn còn luyện tập Tiếng Anh chứ? "
2) I love watching TV, listening to music, playing games and chatting with my friends"- this sentence can be translated into Vietnamese like this :"Tôi thích xem TV, nghe nhạc, chơi game và tôi còn thích nói chuyện với bạn bè"
3) When I was young, I was a very naughty girl - In Vietnamese: "Khi tôi còn nhỏ (when I was young), tôi là một cô bé rất nghịch ngợm ("cô bé" means a young girl( 0- 12) - to say about boy, u can use the word "cậu bé")
4) When I worked in that company, I was a hardworking staff. In vietnamese:" Khi tôi còn làm việc ở công ty đó, tôi là một nhân viên chăm chỉ". "Còn" which is used in the case 3 and 4 means u have stopped to do that action- it can be understood similarly to the word "used to" in english. And in this case it is always put in a sentence with 2 clauses. "When-clause, then followed by another clause"